TCP/UDP Listen sockets can now be set to IPv6 only

drivers/unix/ip_unix.cpp

@@ -33,6 +33,13 @@
 #include <string.h>
 
 #ifdef WINDOWS_ENABLED
+  // Workaround mingw missing flags!
+  #ifndef AI_ADDRCONFIG
+    #define AI_ADDRCONFIG 0x00000400
+  #endif
+  #ifndef AI_V4MAPPED
+    #define AI_V4MAPPED 0x00000800
+  #endif
  #ifdef WINRT_ENABLED
   #include <ws2tcpip.h>
   #include <winsock2.h>
@@ -90,8 +97,10 @@ IP_Address IP_Unix::_resolve_hostname(const String& p_hostname, IP_Address::Addr
 		hints.ai_family = AF_INET;
 	} else if (p_type == IP_Address::TYPE_IPV6) {
 		hints.ai_family = AF_INET6;
+		hints.ai_flags = 0;
 	} else {
 		hints.ai_family = AF_UNSPEC;
+		hints.ai_flags = (AI_V4MAPPED | AI_ADDRCONFIG);
 	};
 
 	int s = getaddrinfo(p_hostname.utf8().get_data(), NULL, &hints, &result);

drivers/unix/packet_peer_udp_posix.cpp

@@ -119,15 +119,24 @@ int PacketPeerUDPPosix::get_max_packet_size() const{
 	return 512; // uhm maybe not
 }
 
-Error PacketPeerUDPPosix::listen(int p_port, IP_Address::AddrType p_address_type, int p_recv_buffer_size) {
+Error PacketPeerUDPPosix::listen(int p_port, IP_Address::AddrType p_type, int p_recv_buffer_size) {
 
 	close();
-	int sock = _get_socket(p_address_type);
+	int sock = _get_socket(p_type);
+
 	if (sock == -1 )
 		return ERR_CANT_CREATE;
 
+	if(p_type == IP_Address::TYPE_IPV6) {
+		// Use IPv6 only socket
+		int yes = 1;
+		if(setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY, (const char*)&yes, sizeof(yes)) != 0) {
+				WARN_PRINT("Unable to unset IPv4 address mapping over IPv6");
+		}
+	}
+
 	sockaddr_storage addr = {0};
-	size_t addr_size = _set_listen_sockaddr(&addr, p_port, p_address_type, NULL);
+	size_t addr_size = _set_listen_sockaddr(&addr, p_port, p_type, NULL);
 
 	if (bind(sock, (struct sockaddr*)&addr, addr_size) == -1 ) {
 		close();

drivers/unix/socket_helpers.h

@@ -56,8 +56,8 @@ static int _socket_create(IP_Address::AddrType p_type, int type, int protocol) {
 
 	if(family == AF_INET6) {
 		// Ensure IPv4 over IPv6 is enabled
-		int v6_only = 0;
-		if(setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY, (const char*)&v6_only, sizeof(v6_only)) != 0) {
+		int no = 0;
+		if(setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY, (const char*)&no, sizeof(no)) != 0) {
 			WARN_PRINT("Unable to set IPv4 address mapping over IPv6");
 		}
 	}

drivers/unix/tcp_server_posix.cpp

@@ -74,6 +74,14 @@ Error TCPServerPosix::listen(uint16_t p_port, IP_Address::AddrType p_type, const
 	sockfd = _socket_create(p_type, SOCK_STREAM, IPPROTO_TCP);
 
 	ERR_FAIL_COND_V(sockfd == -1, FAILED);
+
+	if(p_type == IP_Address::TYPE_IPV6) {
+		// Use IPv6 only socket
+		int yes = 1;
+		if(setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY, (const char*)&yes, sizeof(yes)) != 0) {
+				WARN_PRINT("Unable to unset IPv4 address mapping over IPv6");
+		}
+	}
 #ifndef NO_FCNTL
 	fcntl(sockfd, F_SETFL, O_NONBLOCK);
 #else

platform/windows/packet_peer_udp_winsock.cpp

@@ -112,15 +112,23 @@ void PacketPeerUDPWinsock::_set_blocking(bool p_blocking) {
 	};
 }
 
-Error PacketPeerUDPWinsock::listen(int p_port, IP_Address::AddrType p_address_type, int p_recv_buffer_size) {
+Error PacketPeerUDPWinsock::listen(int p_port, IP_Address::AddrType p_type, int p_recv_buffer_size) {
 
 	close();
-	int sock = _get_socket(p_address_type);
+	int sock = _get_socket(p_type);
 	if (sock == -1 )
 		return ERR_CANT_CREATE;
 
+	if(p_type == IP_Address::TYPE_IPV6) {
+		// Use IPv6 only socket
+		int yes = 1;
+		if(setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY, (const char*)&yes, sizeof(yes)) != 0) {
+				WARN_PRINT("Unable to unset IPv4 address mapping over IPv6");
+		}
+	}
+
 	struct sockaddr_storage addr = {0};
-	size_t addr_size = _set_listen_sockaddr(&addr, p_port, p_address_type, NULL);
+	size_t addr_size = _set_listen_sockaddr(&addr, p_port, p_type, NULL);
 
 	if (bind(sock, (struct sockaddr*)&addr, addr_size) == -1 ) {
 		close();

platform/windows/tcp_server_winsock.cpp

@@ -69,6 +69,14 @@ Error TCPServerWinsock::listen(uint16_t p_port, IP_Address::AddrType p_type,cons
 	sockfd = _socket_create(p_type, SOCK_STREAM, IPPROTO_TCP);
 	ERR_FAIL_COND_V(sockfd == INVALID_SOCKET, FAILED);
 
+	if(p_type == IP_Address::TYPE_IPV6) {
+		// Use IPv6 only socket
+		int yes = 1;
+		if(setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY, (const char*)&yes, sizeof(yes)) != 0) {
+				WARN_PRINT("Unable to unset IPv4 address mapping over IPv6");
+		}
+	}
+
 	unsigned long par = 1;
 	if (ioctlsocket(sockfd, FIONBIO, &par)) {
 		perror("setting non-block mode");